Dad blood: if DNA tests prove that you're not your children's father, do you still owe child support? (Columns).

IMAGINE RAISING A family for years, only to find out one day that your children are not really yours.

Imagine, after the divorce, being told by the courts that you have to continue paying financial support for these children.

Is this a Kafkaesque nightmare, or an unfortunate necessity to protect the children's interests?

No one knows exactly how many men--and children--around the United States are confronting this question in their own lives, but the individual cases that have made it into the spotlight are wrenching.

One such story, told recently on NBC'S Dateline, is that of Morgan Wise, an engineer in Big Springs, Texas. Wise's fateful discovery, several years after his divorce, was prompted by the desire to help treat his 6-year-old son for cystic fibrosis: When he took a blood test to find out which cystic fibrosis gene he carried, it turned out that he didn't have the gene at all. Both parents have to be carriers for a child to inherit the gene.

Subsequent genetic tests showed that of the four children born to Wise's former wife during their 13-year marriage, only the eldest was his. "I never experienced a heart attack, and I can tell you, I had one that day;' Wise told Dateline. "I mean...a part of me died."

When Wise went to court asking to be relieved of the child support payments that consumed a third of his take-home pay, he was turned down. Wise was later barred from contact with all four children because he had discussed the issue of their parentage with them in violation of the judge's order, but he still had to keep the checks coming. In January the U.S. Supreme Court declined to hear Wise's appeal.

To some extent, Wise and others in his position are victims of a gap between law and technology. The law basically presumes, as in ancient Rome, that a woman's husband is the father of any child born during the marriage. While a court may rule in favor of the cuckolded husband, what legal precedent exists is not on his side. Rulings in Pennsylvania, New Hampshire, Rhode Island, and California have also held that if the husband acknowledged the children as his for the duration of the marriage, he cannot deny paternity afterward.

When it comes to unmarried fathers, the law is more flexible, but a man who did not initially dispute a paternity claim may also find it tough to do anything about it later, particularly if he at some point acted as a father to the child. In Georgia, Carnell Smith, now 41, voluntarily assumed responsibility for a child his former girlfriend told him was his, paying more than $40,000 in child support during an II-year period. In 1999, when the mother went to court to seek more money, Smith, by then married with two children, sought genetic testing and learned that he wasn't the girl's father. The courts were not swayed, and by now Smith's total child support bill has reached $120,000.

The 1996 federal welfare reform law directs that voluntary acknowledgment of paternity by an unwed father should be treated as a conclusive and binding establishment of paternity, although it allows for a 60-day rescission period; a 2000 Department of Health and Human Services report on paternity establishment strongly urged state child support collection agencies to follow these guidelines and to encourage the courts to do so as well. Interestingly, the report also noted that over 40 percent of local child support agency staffers surveyed supported genetic testing for putative fathers. Many of these employees felt that affidavits acknowledging paternity were often signed in the flush of excitement over the birth of a child, and some even expressed concerns that a mother's new boyfriend might acknowledge paternity knowing that he was not the father, "out of kindness, pity or foolishness."

At present, four states--Louisiana, Colorado, Iowa, and Ohio--allow men to use DNA tests to disprove previously acknowledged paternity. Similar "paternity fraud" legislation is pending in California and in Georgia, where the initiative has been spearheaded by none other than Carnell Smith.

It might seem like a matter of simple justice. Why should a man support a child who isn't his? If DNA testing can be used to exonerate people accused of rape or murder, why not use it to exonerate men accused of fathering children?

Nevertheless, such proposals remain controversial. Earlier this year, an editorial in The Atlanta Journal-Constitution noted that the Georgia bill dealing with DNA and paternity was "moving forward at an alarming pace" and warned, "Somebody in the General Assembly needs to apply the brakes to it quickly."

What exactly is the peril opponents of such legislation are trying to avert? One common response is that one has to consider the best interest of the children. Yet the exoneration of a falsely accused "father" does not mean that no child support will be paid; the real "culprit" can be pursued instead. Morgan Wise, for instance, has unsuccessfully tried to argue that his former wife's lover or lovers who fathered the three boys he once believed to be his should be the person or persons paying child support.

Moreover, paternity fraud often ends up robbing its victims' real children. Bert Riddick, a California father of three, has spent the last II years paying child support for a girl he has never met, a girl whom DNA tests have shown to be someone else's daughter. As a result, he and his family have had to move in with his brother-in-law, in whose house the three children are crammed into one room. His wife has had to go on welfare.

Critics of paternity fraud legislation also emphasize the social, emotional, and psychological damage children are likely to suffer when Daddy suddenly discards them. And there is no doubt that children get badly hurt. Morgan Wise may have been shafted by the system, but it's difficult to view him with unalloyed sympathy when one learns that, after losing his claim for relief from child support payments, he took his battle public--with the inevitable result that the rumors reached the boys' school, and he ended up telling them he wasn't their real father.

"Regardless of the circumstances of conception, for the child this is the only father he or she has known," Los Angeles attorney Jenny Skoble, director of the Child Support Project at the Harriett Buhai Center for Family Law, wrote recently in Insight magazine. "If this man disappears from the child's life, the child not only loses his financial support, but suffers the well-known emotional effects of being abandoned by a parent."

That's often true, and it's unfortunate (though it is worth noting that the women's advocates typically making these arguments rarely show much concern about divorced fathers' complaints that their ex-wives intentionally disrupt visitation). Yet the reality is that no court can force a parent to be emotionally involved with his children and to participate actively in raising them. A court can only force him to pay up. It's true that courts sometimes bar the alleged father not only from using DNA test results in a paternity challenge but from having the children tested, so as to avoid potentially traumatizing them. Even so, a father who is unsure of his paternity may well withdraw from the children.

It is sad, of course, when a man who has been a de facto father to a child for years suddenly and abruptly abandons him or her. (Conversely, there is something self-serving and opportunistic about the position of some fathers' advocates that a man who has learned that his child is not biologically his should be able to continue contact and visitation but shouldn't pay child support.) But surely a good portion of the blame for such tragic situations rests with mothers who cheat and lie. The men who fight back don't necessarily believe, as some critics claim, that biology alone makes you a father; often, they are reacting to being deceived and used.

"What you're saying is that all a man is, in terms of a father to a child, is a sperm donor," Paula Roberts of the Center for Law and Social Policy in Washington, D.C., told the Los Angeles Times. "We think that's really bad social policy." Agreed. But our current social policy all too often reduces a man to a cash machine.

Contributing Editor Cathy Young ([e-mail]) is a columnist for The Boston Globe.